The invention relates to a cardiac assist catheter pump, to components therefor and to a method for assisting the action of an ailing heart.
From U.S. Pat. No. 3,995,617 a heart assist catheter pump is known which includes a catheter having a distal end for insertion from the aorta past the aortic valve into the left ventricle. The distal end has inlet openings and a check valve for allowing inward flow. Spaced from the distal end, the catheter has outlet openings and a set of second check valves for allowing outward flow. A pump device communicating with the proximal end of the catheter alternatingly generates a suction causing blood to be withdrawn from the left ventricle into the catheter and to the pump device and an excess pressure causing blood to be reintroduced via the set of second check valves into the heart on the downstream side of the aortic valve.
The second check valves are each formed by an elastic booth at the outside of the catheter. A disadvantage of such a catheter is its use entails a risk of thrombosis. Moreover, such a catheter is of a complicated construction and costly, because valves have to be mounted in the catheter and, at another position in longitudinal direction, to the outside of the catheter.
Another example of such a catheter pump is known from U.S. Pat. No. 4,014,317.
It is an object of the invention to provide a solution allowing to assist the action of an ailing heart, which overcomes the above-identified problems.
According to the invention, this object is achieved by providing a cardiac assist catheter pump in which the valve arrangement includes a valve body movable between an inlet position obstructing flow through the outlet passage and allowing flow through the inlet passage and an outlet position obstructing flow through the inlet passage and allowing flow through the outlet passage.
The invention further provides a catheter with such a valve arrangement. A further embodiment of the invention is formed by a fitting for a cardiac assist catheter including:
a tube shaped housing having a coupling for coupling to a distal portion of a catheter on one end and a coupling for coupling to a proximal portion of a catheter on an opposite end; a first passage through the coupling for coupling to a distal portion of a catheter; a second passage through the coupling for coupling to a proximal portion of a catheter; a third passage communicating with the first and second passages; and a valve body movable between an inlet position obstructing flow through the third passage and allowing flow through the first passage and an outlet position obstructing flow through the first passage and allowing flow through the third passage.
Such a catheter and such a fitting are specifically adapted for use as a part of such a catheter pump.
Since the valve arrangement includes a valve body movable between an inlet position at least substantially blocking the outlet passage and clearing the inlet passage and an outlet position at least substantially blocking the inlet passage and clearing the outlet passage, a single valve performs the tasks of alternatingly closing off and clearing of the inlet passage and the outlet passage. With the reduction of the number of valves, the risk of thrombosis occurring at the valve is accordingly reduced and the complexity and costs of the construction are reduced.
Particularly advantageous embodiments of the invention are set forth in the dependent claims. Catheters and fittings according to such particular embodiments are preferably included in the catheter pump according to the invention.
Further objects, features, effects, advantages and details of the invention are described with reference to examples shown in the drawings.